Conventionally, a surveying operation system (RTK surveying method) is known. The system includes a fixed station disposed at a reference point (an observation point at which the fixed station is positioned), where the position coordinate is known, and a mobile station disposed at an observation position, where the position coordinate is unknown. The system receives positioning data from satellites at the fixed station and mobile station while moving the mobile station, and determines the position coordinate of the unknown observation point using the mobile station by correcting the received data with observation correction data sent from the fixed station (see Patent Literature 1, Patent Literature 2, JP2007-271429A, for example).